Risa, Joelle and Gem each had some balls and decided to play a game with their balls. In round 1, Risa lost
12 of her balls to Joelle. In round 2, Joelle lost
12 of her total number of balls to Gem. In round 3, Gem lost
12 of her total number of balls to Risa. In the end, Risa, Joelle and Gem had 124, 88 and 53 balls respectively. How many balls did Joelle have at first?
|
Risa |
Joelle |
Gem |
Before 1 |
2 b |
105 |
|
Change 1 |
- 1 b |
+ 1 b |
|
After 1 |
1 b |
176 |
|
Before 2 |
71 |
2 u |
|
Change 2 |
|
- 1 u |
+1 |
After 2 |
|
1 u |
106 |
Before 3 |
|
|
2 p |
Change 3 |
+ 1 p |
|
- 1 p |
After 3 |
|
|
1 p |
Comparing Risa, Joelle and Gem in the end |
124 |
88 |
53 |
Working backwards.
1 p = 53
At the start of Round 3:
Number of balls that Gem had
= 2 p
= 2 x 53
= 106
At the start of Round 2:
Number of balls that Risa had
= 124 - 1 p
= 124 - 53
= 71
At the end of Round 3:
Number of balls that Joelle had = 88
1 u = 88
At the end of Round 1:
Number of balls that Joelle had
= 2 u
= 2 x 88
= 176
1 b = 71
At the end of Round 1:
Number of balls that Risa had = 71
At the start of Round 1:
Number of balls that Joelle had
= 176 - 1 b
= 176 - 71
= 105
Answer(s): 105